The present invention generally relates to a control apparatus for an internal combustion engine of a vehicle, in which an operating state of a starting motor for starting the internal combustion engine is detected so as to actuate an internal combustion engine start control device to operate in starting of the engine, and particularly relates to an internal combustion engine control apparatus of the type described above provided with a starting motor having a permanent magnet as a field magnet.
In an internal combustion engine control apparatus provided with a permanent magnet type starting motor, which is known, for example, in Japanese Patent Unexamined Publication No. 55-46064, a start control device (for example, a starting fuel increasing device, or the like) actuated to operate in starting or cranking of the internal combustion engine is arranged to be actuated upon detection of a voltage applied to a solenoid coil of a magnet switch provided for driving/stopping the starting motor.
In such a case as described above where the magnetic field of the starting motor is provided by a permanent magnet, however, there has been a problem that an induced voltage generated in the starting motor even after turning-off of a key switch, may be applied to the solenoid coil of the magnet switch and this voltage applied to the coil of the magnet switch is detected as if the starting motor is operating.
This erroneous detection may actuate the start control device to operate at an undesired time. For example, in a start control device provided with fuel increasing means for increasing fuel in starting of the internal combustion engine, the fuel increasing operation is continued even after the starting motor has been stopped, resulting in such a problem that a failure in firing of the fuel may be caused or an exhaust gas becomes dirty too much because of the excessive fuel supply.